Method of determining well volumes



Aug. 6, 1935. L. L. FOLEY 2,010,755.

METHOD OF DETERMINING WELL VOLUMES Filed June 16, 1933 v dummq PatentedAug. 6, 1935 UNITED STATES PATENT} OFFICE.

METHOD OF DETERMINING WELL- VOLUMES This invention relates to the methodof determining cement required for filling the space between a wellcasing and a hole having irregular surfaces.

'5 The primary object of the invention is to provide means for measuringthe capacity of irregular well openings to insure the use of suificientcement to produce a proper shut-off between the well casing and openingfor preventing oil 10 and gas from the pay zone leaking around thecasing, also thereby preventing the leakage of water from shallowsands-into the pay zone and to likewise prevent gas from shallow sandsentering the annular space and escaping outside the casing. e i

In the art of casing wells, by the introduction of tubes or pipes it isnecessary to fill the space between the tube or shaft and the opening inthe ground in which the tube or shaft is placed so as 0 to anchor thecasing and prevent its displacement. After the well has been drilled,portions of the wall thereof will cave in thereby forming a circularwall having many irregular surfaces.

According to the prior practice, the cement is 3 introduced between thewell casing and the well hole merely by guess work and quite frequentlyinsuificient amounts of cement are introduced to insure of propershut-ofi of water, oil and gases from and between the well and casing.

9 The present invention entirely eliminates the guess work in connectionwith cementing well casings in well openings by providing a method ofdetermining the exact volume between the outer wall of the well casingand the well where- 5 by the operator may mix the exact amount of cementrequired for the job.

Other objects and advantages of the invention, will become apparentduring the course of the following description, forming a part of the 9specification and in which,

Figure 1 is a cross-sectional view taken through an area of stratabearing earth illustrating the well and the first string casing placedtherein before the introduction of the cement; and.

5 Figure 2 is a similar view illustrating the first string casingcemented in place and showing the introduction of the second casingstring prior to being cemented or centered in the well opening.

I In the drawing, wherein for the purpose of illustrating the inventionand wherein like reference characters will be employed to designate likeparts throughout the same, the reference character A will generally beemployed to desigi nate an area of strata bearing earth in which isdrilled a well B. The earth in which the well is drilled may includestrata of limestone 0, water and sand C and shale D.

Usually the first string of well casing extends down through three ormore shale strata as is 5 shown in Figure 1 wherein the referencecharacter E will be employed to designate the first string of wellcasing introduced into the well 13 so as to extend below the secondlimestone strata C. After the introduction of the well casing, it isnecessary to cement the well casing E in the well B to preventdisplacement and to center the well casing for further drillingoperation. This invention contemplates the introduction of a dye whichmay be colored red, blue, yellow or 15 green of a nature as to bedistinctly visible from the mud colored water contained in the wellopening. The dye may be introduced at the bottom of the well casing Eafter which a quantityof liquid may be introduced into the well casing,E until the dye reaches the top of the well opening B and between thecasing. Since the volume, of water or liquid introduced into the wellcasing E has been predetermined and the volume of the casing E known,the exact volume of the space between the outer wall of the casing E andthe wall of the well B equals the volume of fiuid introduced which isdetermined when the dye reaches the top of the well. After the volume ofthe space F has been determined, suf- 3 ficient cement may be mixed tofill such space the entire length of the well casing E.

In Figure 2 is illustrated the spaceF filled with cement G whichcompletely seals the first string casing E in place in the cavity B.

When it is desired to insert the second string well casing H after thewell B has been drilled deeper as shown in Figure 2, the space betweenthe second string casing H and the irregular walled well B may bedetermined in terms of 40 volume similarly to the method abovedescribed. The dye or coloring matter may be introduced into the wellcasing H at the bottom thereof and liquid or fluid pumped into thecasing H, the quantity of which is measured until the dye appears at thetop of the casing H on the outside thereof.

After the dye reaches the top of the well outside. of the casing H theouter space between the wall of the second string casing H and the firststring casing E may have a known volume which may be deducted from theamount of fluid introduced into the second string casing H, the resultof which vwill give the exact volume of the space between the well B andthe lower portion of the second string casing H from a point indicatedby the reference character I to the bottom thereof.

The form of the invention herewith shown and cavity and a well casingtherein while the well' is full of fluid and during such period whichconsists in introducing a coloring matter in the cavity at one endthereof and forcing a measured additional quantity of fluid through thecavity until the coloring matter is visible at the opposite end of thecavity whereby the quantity of fluid caused to circulate through thecavity will equal the volume of the cavity.

2. The method of determining the unknown volume of a space between theouter wall of a well casing and a. well cavity having irregular surfaceswhile the well is full of fluid and during such period, consisting ofthe introduction of a coloring matter at the bottom of the casing,circulating additional fluid of a measured quantity through the casingand cavity until the coloring matter reaches the top of the well betweenthe outer wall of the casing and the inner wall of the cavity wherebythe quantity of fluid caused to circulate through the cavity will equalthe volume of the cavity,

LYNDON L. FOLEY.

